Tapping apparatus.



.No. 835,111. I PATENTED NOVKG, 1906.

' W. NICHOLSON, JR.

TAPPING APPARATUS. APPLICATION FILED DBO.22,1906.

' ,INI/D'ENTOR A/fomey I WITNESSES UNITED STATES PATENT. OFFICE.

WILLIAM NICHOLSON, J It, OF WILKES-BARBIE, PENNSYLVANIA, ASSIGNOR TO WM.H. A FIRM;

Specification of Letters Patent.

TAPPINGIAPP'ARATUS".

Patented Nov. 6, 1906-.

Application filed December 22, 1905. Serial N'o.1293.0'15.

tapping screw-threaded holes in metal blocks and it consists in thenovel construction and combination of the parts hereinafter fullydescribed and claimed.

In the drawings, Figure 1 is a front view of the tapping mechanism. Fig.2 is a plan view of the same. Fig. 3 is a cross-section taken on theline a: a; in Fig. 2.

A is a bed, and B is a head-stock secured to the bed.

C is a face-plate or other similar workholder, which is journaled in thehead-stock and provided with a pulley c or other approved drivingmechanism for revolving it.

D is a foot-stock which is secured to the bed and provided with aspindle d.

E is a hand-wheel, and e is a screw for moving the said spindlelongitudinally, and the said spindle is arranged axially in line withthe face-plate.

All the above-mentioned parts may be the corresponding parts of anyapproved enginelathe, boring-machine, or other similar machine-tool.

F is a tap-holder provided with a socket which is slid over theprojecting end portion of the spindle d. A small screw f is provided forholding the socket on the spindle and preventing it from being displacedaccidentally; but this screw may be dispensed with. The tap-holderisprovided with a guide G at its front end, which is arranged axially inline with the spindle.

H is a tap which is provided with a shank h, which is slidablelongitudinally in the guide G. This shank is provided with an arm I,which projects laterally from it and which rests on a guide 45 on thebed. This arm is preferably removable, and it is provided at one endwith a jaw i, which engages with a rectangular portion h on the shank ofthe tap.

When an engine-lathe is used in carrying out this invention, the guide imay conven iently be a bar secured horizontally in the tool-carriage.The tap is provided with an abutment-disk J and a cylindrical frontendportion 9'. said cylindricalportion and disk, and K representslongitudinal grooves formed in the said A groove j is formed between theNICHOLSON & (30., OF WIIiKES BABRE, PENNSYLVANIA, I

cylindrical portion, level with the bottom of t e said groove.

The tap is provided with a series of tapping-blades a, provided withportions" of screw-threads n on their outer surfaces. represents thecuttingedges of the blades, and p represents projections on the blades:arranged on the same side as the cutting edges. These projections fit inundercut grooves in the cylindrical portion '7' of the tap. Thetapping-blades are made to fit tightly in their retaining-grooves, andtheir rear ends bear againstthe abutment-disk.

The blades are preferably tapered, and the. projections p prevent themfrom tipping in their retaining-grooves. As many cuttingblades asdesired can be used, and large taps of twelve or more inches in diametercan be made to work successfully when constructed in this manner.

The work, such as a block or plate of metal, I

is secured to the work-holder, a hole of suit-, able size being firstformed in it. The front end of the tap is fed gradually into the hole inthe work by-means of the feed-screw and hand-wheel, and the work isrevolved. The tap is prevented from revolving by means of.

the arm I, and it feeds itself automatically into the hole in the work,tapping the said hole as it is moved forward. The spindle is heldstationary after the tap has been moved forward by it into engagementwith the hole,

and the shank of the tap then slides longitudin ally in its guide whilethe hole is being tapped.

When this apparatus is used, it is not necesshank which is slidable inthe said guidea rectangular portion at its middle part, and socket, astationary guide secured parallel a removable arm for preventing thesaid tap Withthe axis of the said tap and tap-holder, from revolvingprovided with a jaw for enand an arm which projects from the said tapgaging with the said rectangular portion. T 5

5 and slides longitudinally on the said guide. In testimony whereof Ihave aflixed my 2. In flapping hmielchanismhtld e combinad signature inthe presence of two Witnesses. tion, wit a tap- 0 er rovi e at one enwith a socket for engaging with a supporting- WILLIAM NICHOLSON spindleand having a guide at its other end, Witnesses: 10 of a tap providedwith a shank which is slid- A. L. TURNER,

able in the said guide, said shank having HARRY S. NICHOLSON.

